The demand for electronic communication of data has exploded in recent years. A variety of technologies have been developed to meet this demand. These technologies deliver data at ever increasing speeds. One technology for delivering data is referred to as digital subscriber line (DSL) technology. DSL technology encompasses a variety of technologies including but not limited to asymmetric digital subscriber line (ADSL), symmetric digital subscriber line (SDSL) including G.SHDSL, high bit rate digital subscriber line (HDSL), very high bit rate digital subscriber line VHDSL, and rate adaptive digital subscriber line (RDSL). In each case, DSL technology delivers high speed digital transmission over existing telephone lines, e.g., twisted copper pairs.
DSL technology typically communicates digital data between cusotmer premises equipment (CPE) and a data network. The customer premises equipment is commonly referred to as a DSL modem or an integrated access device. The data network typically comprises an Asynchronous Transfer Mode (ATM) network or other appropriate data network. DSL technology uses a device known as a digital subscriber line access multiplexer (DSLAM) to facilitate the connection between the customer premises equipment and the data network.
The DSLAM is located, for example, at a central office of the telephone company. A conventional DSLAM includes a number of different cards or boards in a rack or housing. In one conventional approach, the DSLAM includes at least one line card that provides connection to the data network over one or more high capacity lines, e.g., an OC-3 line, a DS-3 line or other appropriate high capacity line. The DSLAM also includes a control card that controls the operation of the DSLAM, e.g., allows configuration, monitoring and control of the DSLAM. Further, the DSLAM also includes a number of channel cards, e.g., cards that provide connection to a number of modems over a number of telephone lines or twisted pairs.
The various boards or cards of the DSLAM communicate with each other to connect the customer premises equipment with the data network. This intra-DSLAM communication is accomplished over a cell bus that typically resides on a backplane in the rack of the DSLAM. This cell bus is used to carry traffic between cards, e.g., between line cards and the channel cards, in the DSLAM to effectuate communication to and from modems.
The cell bus is also used to carry other communications between cards in the DSLAM. For example, inter-board communication has typically been accomplished between the control card and the other cards over a dedicated VPI on the cell bus using private IP addresses.
Many functions have been typically carried out on a single board in the DSLAM. However, to improve performance of some of these functions, it is desirable to split the functionality between multiple cards in the DSLAM. For example, traffic management has typically been performed in line cards. It would be desirable to perform traffic management using multiple cards, e.g, the line card and a channel card. Unfortunately, functions like traffic management are often time critical and conventional inter-board communication may not be fast enough to allow splitting of the functionality between multiple cards. Therefore, there is a need in the art for faster communication between boards in a DSLAM to allow splitting of functionality between cards.